Study On The Synthesis And Drug Release Performance Of Ordered Mesoporous Thin Films

Owing to their various framework compositions,fascinating pore architectures and large porosities,ordered membrane materials have triggered substantial research interests in material science,and possess great potential for the applications in energy,environment and human health fields.Recently,great progresses in synthesis,property study and application of the mesoporous thin film materials have been realized.However,there still have some challenges in developing new functions of the mesoporous membrane materials in drug transportation.Based on the demand of the functional application in biomedicine,this thesis focuses on the synthesis,property research and application of mesoporous thin films.Mesoporous silica thin films with controllable thickness have been successfully synthesized via a solvent evaporation induced self-assembly process using triblock copolymer Pluronic F127 as a template and tetraethoxysilane（TEOS）as a silicon source.The resultant films possess highly ordered mesostructure in centimeter scale,uniform mesopore size（7.1 nm）and high specific surface area（649 m²/g）.More importantly,the thickness of the obtained silica films can be well-adjusted from 100 to 300 nm.The drug loading and release behavior of mesoporous silica thin films were evaluated under different pH conditions using weal base type anti-cancer drug doxorubicin hydrochloride（DOX）as a model drug.Owing to the electrostatic interaction,the release of DOX from silica thin films is pH dependent,which release slowly under physiological conditions while deliver quickly under acidic conditions,indicating that the acid-sensitive drug delivery could be achieved by the mesoporous silica thin films.The NH₂-functionalized mesoporous silica thin films with controllable loading capacity have been successfully synthesized by a post-modification strategy utilizing ordered mesoporous silica film as the host material and（3-aminopropyl）triethoxysilane（APTES）as an ammonia source.The hydrophobicity of the films are improved by grafting organosilane on the surface of the channel without damaging the original mesoporous structure,thus increasing the loading capacity of DOX.The DOX release performances of mesoporous silica thin films before and after post-modification under different pH conditions were further studied,it is found that the NH₂-functionalizd silica thin films present pH-sensitive sustained release behaviors and possess longer half-life and lower side effects,which shows a great application prospect in the field of biology and medicine.The highly ordered mesoporous carbon thin films with large aperture and controllable thickness have been successfully synthesized via a sol-gel process utilizing diblock copolymer polyepoxide-b-polystyrene（PEO-b-PS）as a template agent,resol as a carbon source.The obtained mesoporous carbon thin films possess ordered three-dimensional（3D）connected mesostructure on the centimeter scale,large mesopore size（24 nm）,controllrable thickness of film and high specific surface area（524 m²/g）.The mesoporous carbon thin films are used as carriers of hydrophobic anti-cancer drug,investigating the drug loading and release behavior of mesoporous carbon thin films.The results indicate that the mesoporous carbon thin films with controlled thickness not only possess the pH-response gating mechanism,but also own higher drug loading amounts and release percentages due to the large pore size,3D connected channel structure and rich surface charge.